1-{5-[(5-{[(2R)-2-ethylpyrrolidin-1-yl]methyl}-4-[4-methoxy-3-(trifluoromethyl)phenyl]-1,3-thiazol-2-yl)carbamoyl]pyrazin-2-yl}pyperidine-4-carboxylic acid (hereinafter referred to as compound A in some cases) is represented by the following chemical structural formula. Compound A has a muscarinic M3 receptor positive allosteric modulator, and is known to be useful as an agent for preventing and/or treating bladder or urinary tract diseases related to bladder contraction by a muscarinic M3 receptor (Patent literature 1).

In order to improve the disintegration properties of poorly-soluble drugs, a composition comprising a solid dispersion of a drug with a gel-forming water-soluble polymer, and a salt substance that comprises an alkali and a weak or strong acid and has an endothermic standard enthalpy of solution or heat of solution, is known (Patent literature 2).
In order to improve a dissolution rate and bioavailability, an invention, which relates to a rapidly disintegrable pharmaceutical composition which comprises a poorly-soluble drug held on a gel-forming water-soluble polymer as a solid dispersion, wherein it contains a salt substance that comprises an alkali and a weak or strong acid and has an endothermic standard enthalpy of solution or heat of solution, has been proposed (Patent literature 3).
There are some drugs having poor solubility due to not only having simply low solubility but also their properties, such as pH-dependent solubility, or gelation characteristics through contact with water.
Therefore, there is still room for improvement in providing a formulation, in which the dissolution properties of a poorly-soluble drug are improved, and the oral absorbability is improved.